Mill roll scraper



Sept. 23, 1958 A. JACOBSON MILL ROLL SCRAPER 2 Sheets-Sheet 1 FIG. 2.

led April 27, 1955 INVENTOR. 145N497? l/AC0550/V BY Sept. 23, 1958 A.JACOBSON MILL ROLL SCRAPER 2 Sheets-Sheet 2 Filed April 27, 1955 5 v, 4mm ME 7 T 0 a N m5 mp VB m m Mr A W F 1 5 m N 4 w a United StatesPatent"- MILL ROLL SCRAPER Abner; Iacnbsong. Shaker. Heights, OhioApplication Aprili27,1955,,SerialjN0. 504,210 liClalmst (61;;241-467)The present invention, relates to i'mproved'millroll apparatus. andmore. particularly. to floating scraper apparatus adapted toredistribute the milled material onv handle'is'particularly wellexemplified by a mixture of fine graphite particles. in. a stickyhydrocarbon matrix in which-the graphite particles are being milled downto a substantially uniform. colloidal size. Such types of sticky viscousmaterialsclog up the spaces between the ends of the rollers and the.frame of the mill. Bearings become clogged; proper lubrication isprevented and rapid wear and overheating occur. Large quantities of themilled.

material are lost and contaminated with lubricating oil. Frequentshutdowns are caused.

It has become common practice to use wiping glands at opposite ends ofthe. rolls inan effort to plow the milled material away from their endsand turn it back in toward their medial portions. A .pair of thesewiping glands is used with each roller. These glands have generallysaddle shaped faces which are pressed firmly into contact with thesurface of each roll' near opposite ends. In many cases the saddle faceof the gland extends around a. substantial party of the circumference.of the roll. Nevertheless, where the material .is extremely sticky andviscous it adheres firmly to the surface of the roll. As the roll turnsthe material soon begins to be pulled in under the front edge ofthesaddle. The material acts like a thin wedge as it works back underthe wiping gland and lifts.

it away from the surface of the roll. In a short while a substantialclearance exists between, the roll surface and the saddle over the fullcircumferential length of the saddle. This lifting effect occursregardless of the application'of extremely great forces to hold thegland down, and in many cases the forces must be reduced to preventoverheating and damage to the mill or spoilage of the material.

Then, when the gland'is lifted, the material creeps on out over the endof the roll almost as fast as if the.

wiping gland were not used. Once the gland is pried up by the materialfrom the roll surface it, is practically impossible to force it backdown with the mill in operation.

This problem of the creep out of the milled material is'even moredifficult to deal with in the types of mills ice where, at least one of,the rollers is slightly crowned and its bearings are purposely providedwith lateral play The. crownedroller thus is. allqwedto wobble slightlyas, the mill turnscausing amorerapid redistribution of the milledmaterialover the millroll, surfaces. andproducing a more complete,undunifbrm, milling operation. The wiping landsthenmust. float? inoperatien t fnllowthe. wobblingofthemillrollli As aresult the. milledmate.- ria1.c.an..cre p.under. the. Wiping gland more easily than whenthe. rolls. are fixed...

It, is an object, of the. present; inventionto provide,- flfoatingscraper apparatus which. is h ghly. successful, in oyercomingthisproblem, of the creeping of milled. mate.- rialidutonto he. end ofthe.roll rs and, tQ'enable mills. of the, rolljtype .to handle, stickyviscous materials more, efii'ciently and withless; wear, andshutdowns,

In. accor ance .with. the descri ed embodiment f the present invention,the floating scraper apparatus, is ar-' ranged to scIaPQthe milledmaterial away from the surface. o amillmll he dof'the w n ng gland. The.milled material iscontinuquslyturned back in toward'the center of: the.rol1S.-..

Amongthe. many. advantages of the. illustrative :embodirv men ofjthe.presentinv nti n ar those-res lting from he factthat the. scraperapparatus .isfioating in its operation, thins. ciuitrudu lv. ac ommoding i self. to. movem nts. of the mill; rollandwiping gland.Substantially complete removalof'the milledmaterial. away from the rollsurface ahead" of the wi'ping glandisv obtained. The materialis; alsoeffectively prevented, from. creeping off of the. end of the roll. Thus,the wiping glandcanbe operated at reduced pressures, resulting in, lesswear, and heat, and

invention, but it is to be understoodthat it is not intended.

to be exhaustivenor limiting ofthe inventiombut on the contrary is givenfor purposes of illustration inZorder that others skilled. in the artmay. fully understand the invention and the manner of applying it inpractical use so that they may modify and adapt it in various forms,each as may be bestsuited to the conditions of a particular use.

The various objects, aspects, and advantages of the pres-, ent inventionwill be more fully understood from a consideration of the followingspecification in conjunction with the'accompanying drawings, in which:

Figure-.1 ista partial perspective viewof a mill roll with associatedfloating rolli scraper apparatus. embodying the presentinventiong-- Fgure; i553, top view of, apair of mill rolls including;

scraper, apparatus; asshown; in Figure l andwiththeassociated hydrauliccontrol systenrforthe, scraper apparatus schematicallyillustrated;Figure3 isaperspectiveview, on enlarged scale, of, the

scraper shown, in Figure 1, the view being taken in the. generaldirection of the arrows. 3--3, that is, looking upwardly in Figure 1from a position below and to the left of the scraper;

Figure 4 is another perspective view of the scraper as seen looking upand to the right in Figure 3 from the line 44 as indicated;

Figure 5 is a top view, partially in section and on enlarged scale,taken generally along the line 5-5 in Figure 1 looking downwardly; and

Figure 6 is an elevational and partial sectional view as seen looking tothe right in Figure 5 in the direction of the surface of the roll, thesection being indicated by the line 66.

In operation the viscous material to be milled is fed to the surfaces ofthe front and rear mill rolls 10 and 12, respectively, in Figure 2approximately midway between their ends. The front roll 10 is rotated ina counter-clockwise direction as shown by the arrow 14 in Figures 1 and6 and the rear roll 12 is rotated in the opposite direction so that thematerial is drawn down into the crotch 16 between the rolls and crushed.The material adheres to the surfaces of the rolls and is continuouslycarried underneath them and up around them again and again for repeatedcrushing. In order to improve the milling effect, the front roller 10maybe of slightly smaller diameter than the rear roller, for example, itmay be 22 inches in diameter compared with 24 inches for the rearroller. Also, it may be rotated at a slightly slower speed than the rearroller, for example, such as 40 R. P. M. compared with 45 R. P. M.,respectively. Also, the surface of the front roller may be crownedslightly and its bearings may be provided with lateral play at theirmounting points in the left and right side frames 18 and 20,respectively. This play enables slight wobbling of roll 10 relative tothe roll 12, which has its bearings rigidly secured in place in theseframes, thus producing a better action in distributing the materialalong the surfaces of both mill rolls.

Soon after the mill rolls begin to turn, the material becomessubstantially uniformly spread over the surfaces of the rolls and creepsout toward their ends. Pairs of wiping glands 22 and 24, and 26 and 28are located at opposite ends of the rolls 10 and 12, respectively, andhave saddle surfaces sitting down astride the tops of these rolls. Asshown in Figures 1 and 2, the adjacent edges of these glands arerabbeted and interfitted along vertical joints 30 and 32, effectively towall up the left and right sides of the crotch region 16, respectively,so as to retain any excess material therein. The front inside corners ofthese wiping glands are rounded off. For example, as shown in Figure 5,the front inside face of the gland 24' is defined by a convexcylindrical surface 34 tangential with the inside face 36 of the gland24.

In order to prevent the material from wedging under the gland 24 and toprevent it from creeping out to the end of the roll -(see Figures 5 and6), a floating scraper 38 is pressed down firmly against the rollsurface ahead of the wiping gland. This scraper is generally L-shaped asseen from on top. It has a rearwardly extending side portion 40extending back adjacent the convex surface 36 of the wiping gland and afront portion 42 extending across in front of the wiping gland andoverlapping the adjacent end 43 of the roll 10. The outside face 44 ofthe side portion 40 resting against the convex surface 34 of the gland24 is also rounded to provide a slightly convex bearing surface. Bytilting and rocking the scraper on these convex bearing surfaces, theadjustment of the scraper into optimum operating position is obtained,as explained below. In effect, these bearing surfaces permit limiteduniversal motion between the scraper and the gland.

To secure the scraper 38 in position while allowing adjustment andfloating action thereof so as to accommodate any slight wobbling of theroll 10, a bolt 46 is passed through a hole 48 near the effective centerof the side portion 40. The bolt extends in a direction parallel to theaxis of the roll 10 and serves as an axis about which a limited degreeof universal adjustment of the scraper 38 is made. The diameter of thehole 48 is considerably larger than the shank of the bolt with a sleeve50 fitting loosely therein around the bolt shank and preventing thesurfaces 34 and 44 from being tightly clamped together. The end of thesleeve 50 thrusting against the surface 34 is cut off at an angle equalto the angle of the surface 34 around the bolt shank, and the other endbears against the underside of the bolt head. Freedom for adjustment ofthe scraper 38 is provided by the clearance within the hole 48 and bythe sleeve 50 which prevents the bolt from being drawn up too tightly.As shown in Figure 5, a nut 52 and an associated lockwasher and a washerwithin a recess 54 in the outside of the gland 24 hold the bolt inplace. It is desirable to have the bolt head of a screw type andcountersunk below the inside face of the side portion 40, thus allowingthe milled material to slide back alongside of the scraper 38 withoutinterference.

Extending across the bottom of the scrapper 38 is a scraping edge 56pressed firmly into contact with the surface of the roll. This edge isformed by the junction of a concave trailing face 58 of the scraper 38(see also Figures 3 and 4) which is cylindrical and has its axisextending parallel with the axis of the hole 48 with a plow face 60extending generally diagonally up and across the front of the scraper 38and facing the oncoming surface of the roll. The junction of these twosurfaces along the edge 56 is seen most clearly in Figure 4. As shownmost clearly in Figures 1 and 3, this plow face starts at the mostadvanced portion of the scraper at a tip 62 and slopes upwardly at anangle C (Figure 3) of about 50 with respect to the substantiallyvertical corner 65. planar, and the scraping edge 56 is curved in agenerally helical shape to conform to the surface of the roll 10.

To illustrate the way in which the scraping edge 56 begins at a pointoverhanging the end 43 of the roll 10 and slants inwardly to force themilled material back in toward the center of the roll 10, reference isalso made to the dotted line 56 in Figure 5 showing the relativeposition of the edge 56 extending across the under side of the scraper38 as seen from a top view. It is to be noted that the effective pointof support of the convex bearing surfaces 34 and 44 is always close tothe position where the bolt 46 enters the wiping gland. Thus, thisbearing point is approximately directly behind the mid-point of thescraping edge 56 in an axial direction. Also, as seen in Figure 6, thishearing point lies on a line 63 tangent to the roll at a point near themiddle of the scraping edge 56. Line 63 is tangent to the surface of theroll 10 at a point approximately in the center of the scraping edge 56,

' that is, halfway along the dashed line 56 in Figure 5.

In order to plow the material inwardly of the roll while at the sametime folding the material over on top of itself with an advantageouskneading action, the plow face 60 (see Figure 6) overhangs the oncomingsurface of the roll. As shown in this illustrative embodiment of theinvention, the plow surface 60 forms an approach angle A as measuredbetween the surface 60 and the adjacent surface of the roll in a planeperpendicular to the roll axis of about 35 with respect to the surfaceof the roll 10 thereunder immediately adjacent to scraping edge 56. Thedashed line 64 represents the direction of the radius of the rollpassing through a point on the edge 56 adjacent the inner side of thescraper 38, and the plow face is directed forward of the extension ofthis radius by the complementary angle B of 55 at this point, that is,is directed toward the oncoming roll surface.

As mentioned above, the lower trailing face 58 of the scraper issubstantially cylindrical. In order to cant the scraper and adjust itsangular position so that this trailing face is in contact with the rollonly along the edge 56,

In this embodiment the plow face 60 is an adjustable abutment means isprovided by a set screw 70 threaded through a hole 72' in'theupper'corner of the front portion 42 of scraper 3C- spaced' aconsiderable distance above its tip 62. This set screw thrusts againstthe front ofthe'wiping gland 24 so as to tilt slightlythe body of thescraper and rock it in an axial direction of the roll about the point ofcontact between the rounded bearing surfaces 34 and 44.

In order to prevent the milled material from collecting behind thescraper, I have found it advantageous to taper back the side portion 40of the scraper. This may conveniently be done by cutting it off atanangle of about 45 forming a taper 73.

Forcing the edge 56firmly against the roll is a pressing member 74having a rounded end engaging in a rounded pocket 76 in the trapezoidalshaped front face 77 of the scraper 38; This member presses radially ofthe roll 10 as indicated by the dashed line 78, and as shown it isinclined at an; angle of about 45 with respect to a vertical planeincluding the axis of the-roll. Also, it thrusts axially outwardlytoward the roll end 44 at an angle of about with respect to a planeperpendicular to the roll-axis.

Advantageously, the direction of action of the thrust of member 74intersects the scraping edge 56 near its mid point. Thus, the pressureis substantially uniform along the edge 56. Also, because the member 74acts radially of the roll, it has no tendency to push the scraper 38 outof its adjusted position. With the roll 10 turning, the set screw 70 istightened against the front edge of the wiping gland until the trailingface 58. is lifted up a very slight amount away from the roll, leavingonly the edge 56 firmly in contact with the roll.

To supply'the desired amount of force to the member '74; a hydrauliccylinder 80 is supported at an angle. of

about 45 from the end of a bracket 82 suitably secured,

as by bolts 84, to inside face 36 of the gland 24 a considerabledistance above the surface of the millroll; A

base plate 86 is welded to the end, of the bracket -82.at.

the desired angle and the cylinder 80 isv thenbolted to this plate.

As-shown in Figure 2, a scraper 37 is associated with.

the wiping gland 22 and scrapers 39 and 41 are associated with thewiping glands 26' and 28 of the rear roll. Operating each of these otherthree scrapers are hydraulic cylinders corresponding with the cylinder80. The supporting brackets for these cylinders are not illustrated inFigure '2 for purposes of simplification. Hydraulic fluid is suppliedfrom a reservoir 90'through a positive displacement type pump 92 andthrough'a' high pressure line 94 to a control valve 96 which returns acontrolled portion of the fluid back through a line 98 to the reservoir.The fluid at the desired pressure is fed throughra front branch line 100to the cylinders for the front roll scrap-. ers and is fed througha rearbranch line 102' to the others. Return lines are indicated at 104 and106'leading back to the pump intake.

Among the many advantages of this scraping apparatus is that the scraperis entirely supported from its associated wiping gland. Thus, as thefront. roll wobbles in operation the scrapers automatically move withtheir wiping glands. Moreover, the scrapers are floating" free for alimited amount of motion with respect to the, gland.

and with respect to the. mill frame. The pressure is appliedsubstantially uniformly along the scraping edge and is preciselycontrollable by the valve 96.

Where the milled material is a mixture of graphite and.

with pressures of the order of about 100 to 500 poundsper square inchalong the edge 56 and are found to run cool and to keep the rolls cleanat both ends. As a result 6 the wiping glands run smoother and muchcooler, and a mill' can-be run continuously for an' entire day or longerat full output without any of thedifiiculties discussed above.

From the foregoing it will be-understood that theembodiment of thepresent invention described above is well suited to provide the manyadvantages set forth, and since different embodiments: may be made ofthis invention' and as the apparatus herein described may be varied invarious parts, all' without departing from the scopeof the invention, itis to be understood that all matterhere inbefore set forth or shown inthe accompanying'drawings is to be interpreted as illustrative and notin a limiting sense and that in certain instances, some of the featuresof the inventio'nmaybe used'without a correspondinguse of otherfeatures, or without departing from the scope of the invention.

What is claimed is:

1. In a rolling mill having a plurality of rolls for milling material,scrap'er' apparatus deflecting the material in a direction generallyaxially of a roll, said apparatus including a scraper having a scrapingedge at an inclination with respect to the roll axisand engaging thesurface of said roll, said scraper having a plow face and a trailingface meeting along said edge, said plow face overhanging the surface ofthe roll immediately ahead of said scraping edge at an acute angle asmeasured in a plane perpendicular to the axis. of the roll, saidtrailing face closely overhanging the surface of the roll immediatelybehind said scraping edge at all pointsalong the length of said edge andbeing substantially tangent to the surface of. the roll'behind saidedge, and;

defining clearance space between said trailing face and the surface ofthe roll behind. said edge, and a pressing, member forcing said edgedownfirmly against the surface of the roll, the direction of actionofsaidpressing. member being radialy inward of the roll toward its. axisand passing. generally through said edge.

2. In a rolling mill having a plurality of rolls for milling material,scraper apparatus deflecting the material in a direction generallyaxially of a roll, said appara-. tus including a scraper. having a.scraping edge at an. inclination with respect to'the roll axis andengaging the roll surface, said scraper having a plow face overhangingthe roll surface immediately ahead ,of: said scraping ment meansgenerally above the leading end of said" scraping edge and positioningsaid scraper with said trailing face lifted slightly, from the rollsurface and defining a clearance'space between said trailing face andsaid roll surface behind the. scraping edge, and pressingmeans actingradially inwardly of, said roll along aline.

of action passing near said scraping edge.

3. Rolling mill scraper apparatus asclaimed in claim 2 and wherein saidplow face is. substantially planar.

4. Rolling mill scraper apparatus as claimed in claim 3 and wherein saidplow face is inclined. at an angle C of about 50 with respect to a planeperpendicular to the; roll axis: and. said scraping edge is: generallyhelical in shape.

5. In a rollingmill having a plurality of rolls for milling material,scraper apparatus deflecting the material in a direction generallyaxially of a roll, said apparatus including a scraper having avscrapingedge at. an inclinaa tion with. respect to the roll axis andengaging the surface of said roll, said scraper having a plow face and atrailing face meeting along said edge, said plow face overv saidscraping edge at an acute angle as measured in a plane perpendicular tothe axis of the roll, said trailing face closely overhanging the surfaceof the roll immediately behind said scraping edge at all points alongthe length of said edge, bearing means supporting said scraper at apoint, said point being behind said scraping edge and at a positionwhich is generally on a line tangent to the roll surface near the middleof said scraping edge, adjustable abutment means generally above theleading end of said scraping edge and positioning said scraper with saidtrailing face lifted slightly from the roll surface and defining aclearance space thereunder behind said edge, and pressing means actingradially inwardly of said roll along a line of action passing near saidscraping edge.

6. Rolling mill scraper apparatus comprising a mill roll, a scraperhaving a generally helically shaped scraping edge at an inclination withrespect to the roll axis and engaging the surface of said roll, saidscraper having a plow face and a trailing face meeting along said edge,said plow face overhanging the roll surface immediately ahead of saidscraping edge, said trailing face being substantially tangent to thesurface of the roll behind said edge, a pressing member forcing saidedge down firmly against the surface of the roll, the direction ofaction of said pressing member passing generally through the center ofsaid edge and generally radially inwardly of the roll toward its axis,and a wiping gland engaging said roll, said scraper being pivotallysecured to said wiping gland at a point behind said scraping edge.

7. In a rolling mill having a plurality of rolls for milling material,apparatus for controlling the distribution of the milled material duringmilling comprising a mill roll, a wiping gland having a saddle engagingsaid roll near one end, said gland having a front corner, a gen erallyL-shaped scraper adjacent said corner and having a rearwardly extendingside portion extending back beside said gland on the side of said glandfacing away from the nearer end of the roll and having a front portionextending across in front of said gland, said front portion including ascraping edge engaging the roll surface and inclined axially inwardly ofthe roll, and force generating means acting on said scraper and pressingsaid edge against said roll and also forcing said scraper toward saidcorner.

8. Apparatus as claimed in claim 7 and wherein said side portion of thescraper tapers rearwardly toward the adjacent side of said gland.

9. In a rolling mill having a plurality of rolls for milling material,apparatus for plowing the milled material axially inwardly away from theend of a mill roll comprising a wiping gland having a saddle engagingsaid roll near the end of the roll, said gland having a front corner, agenerally L-shaped scraper straddling said corner and having arearwardly extending side portion extending back beside said gland onthe side of said gland facing away from said roll end and having a frontportion extending across in front of said gland and overhanging saidroll end, said front portion including a scraping edge engaging the rollsurface along a line beginning at said roll end and inclined axiallyinwardly of the roll to a position generally inside of said corner, andforce applying means engaging said scraper and forcing it toward saidstraddling position and also pressing said edge firmly down onto theroll surface.

10. In a rolling mill having a plurality of mill rolls, apparatus forconfining the milled material on the roll surfaces comprising: aplurality of wiping glands near the ends of a pair of adjacent rolls, aplurality of L- shaped scrapers, each scraper straddling the forwardinside corner of one of said wiping glands, each scraper having ascraping edge extending inwardly along the surface of the respectiveassociated mill roll ahead of the respective gland which it straddlesand inclined rearwardly, and force applying means mounted on each glandand pressing said edge firmly against the surface of the respectiveassociated mill roll.

11. In a rolling mill having a plurality of mill rolls, apparatus forconfining the milled material on the roll surfaces comprising: aplurality of wiping glands, one being near each of the ends of a pair ofadjacent rolls, a scraper movably secured to each gland and having ascraping edge extending axially inwardly along the surface of the millroll ahead of the respective gland which it straddles and inclinedrearwardly in the direction of rotation of the mill roll which is nearthe respective gland which it straddles, a force-generating cylinderassociated with each gland, bracket means securing each cylinder to itsassociated gland, each cylinder acting to press the scraping edge of thescraper straddling said associated gland firmly against the mill rollsurface, a fluid supply system connected to said cylinders, and means tocontrol the pressure supplied to said cylinders by said system.

12. In a rolling mill having a plurality of rolls for milling material,scraper apparatus for pushing the milled material axially inwardly awayfrom the end of a mill roll comprising a wiping gland having a saddleengaging said roll near one end, said gland having a front corner, agenerally L-shaped scraper straddling said corner and having arearwardly extending side portion extending back beside said gland onthe side of said gland facing away from said roll end and having a frontportion extending across in front of said gland, said front portionincluding a scraping edge engaging the roll surface ahead of said wipinggland and inclined axially inwardly of the roll to a position generallyinside of said gland, a pivot bearing for said scraper pivotallycoupling said side portion to said gland at a point behind said edge, aforce generating mechanism, bracket means supporting said mechanism fromsaid gland and in a position above said scraper, and a pressing memberactuated by said force generating means and exerting force on saidscraper along a line of action passing through said scraping edge anddirected radially inward of the roll.

13. In a rolling mill having a plurality of rolls for milling material,scraper apparatus for plowing the milled material axially away from theend of a mill roll and for folding the material over onto itself duringsaid plowing comprising a wiping gland having a saddle engaging saidroll near the end of said roll, said gland having a front corner facinggenerally axially away from said end, a generally L-shaped scraperstraddling said corner and having a rearwardly extending side portionextending back beside said gland and having a front portion extendingacross in front of said gland, said front portion including a scrapingedge engaging the roll surface ahead of said wiping gland and inclinedaxially inwardly of the roll to a position generally inside of saidcorner, said scraper having a plow face extending up from said edge andoverhanging the surface of the roll immediately ahead of said edge, andforce applying means engaging said scraper and forcing it toward saidstraddling position and also pressing said edge firmly down onto theroll surface.

14. Rolling mill scraper apparatus as claimed in claim 13 and whereinsaid force-applying means is a force-generating cylinder supported fromsaid gland and including a pressing member engaging said scraper andacting along a line directed radially of the roll and passing throughsaid scraping edge.

15. In a rolling mill having a plurality of rolls for milling material,scraper apparatus for deflecting the milled material along the surfaceof a roll away from one end comprising: a wiping gland having a saddleengaging said roll near one end, said gland having an inner front cornerwhich is rounded, a scraper having a rearwardly extending side portionpositioned beside said gland and having a front portion positioned aheadof said gland, said scraper straddling said corner, said side portionbeing connected to said gland for universal motion of the scraper withrespect to said gland, said front portion of the scraper having a plowface commencing at a point near said one'end of the roll and slantingrearwardly and away from said one end and terminating at a pointpositioned axially inside of said corner, adjustable abutment meansinterengaging said front portion and gland, bracket means extendingahead of said gland, and a force exerting mechanism associated with saidbracket means and including a pressing member applying force to thefront portion of said Scrapper and forcing the lower edge of said plowface firmly against the roll, the line of action of said pressing memberbeing directed generally radially inward of said roll and forming an 10angle of about 45 with respect to said front portion of the scraper,said line of action also being canted toward said one end at a smallangle with respect to a plane perpendicular with the roll axis, wherebysaid pressing member presses said side member against the gland.

References Cited in the file of this patent UNITED STATES PATENTSBehringer May 30,

